1. Field of the Invention
This invention relates generally to final drive assemblies for track laying vehicles and, more particularly, to an improved seal arrangement for inhibiting lubricant loss and internal contamination in disengageable final drive assemblies.
2. Description of the Prior Art
In heavy track laying vehicles it is common to provide self contained, planetary gear type final drive units between the track sprockets and the corresponding transmission output shafts to increase the driving torque at the sprockets. In some situations, as when an engine failure occurs, it may be necessary to tow the track laying vehicle to a place of repair or to a transporter. It has been suggested that advantages accrue when such vehicles are towed with the transmission disconnected from the sprockets. Accordingly, in U.S. Pat. Nos. 3,504,563, issued Apr. 7, 1970 to J. C. Polak, and 3,504,564, issued Apr. 7, 1970 to N. B. Kell, both assigned to the assignee of this invention, disconnectable final drive units are proposed. In each of these units a torque transmitting sleeve is shiftable between engaged and disengaged positions to disconnect the sprocket from the transmission output shaft and relatively complex seal arrangements are provided to prevent internal contamination of the final drive assembly and loss of lubricant. A seal arrangement according to this invention represents an improvement in terms of simplicity, economy, and reliability over comparable heretofore known arrangements in similar environments.